And remember that when Realsense is activated it will slow the flight speed to about 11 mph, so one has to decide where the sweet spot is for getting it back in time before the voltage drops too low. This ties in with the thread discussions as to what is the best speed to fly while getting the most time out of a battery.

Great conversation. I never use RTH, but it makes sense to able to set the altitude you want, and be able to turn on OA if you like.
If I have pushed my flight time a bit I do tend to fly a bit faster than RTH to get back.